MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
DECEMBER, 2002
(For general comments about the nature of these summaries, as well as
information on how to download the tabular cyclone track files, see
the Author's Note at the end of this summary.)
SPECIAL NOTE: There has been a change in the address of one of the
archival sites where back issues of the monthly summaries and track
files are catalogued. Chris Landsea has moved the files he was
previously archiving on a computer at TPC/NHC to a machine at AOML/HRD.
The address is:
ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
*************************************************************************
DECEMBER HIGHLIGHTS
--> Typhoon causes severe damage on Guam
--> Extremely intense South Pacific cyclone devastates small islands
in Solomons
--> Southwest Indian Ocean cyclone threatens Mauritius while another
tropical storm strikes Mozambique
*************************************************************************
***** Feature of the Month for December *****
A CLIMATOLOGY OF INTENSE TROPICAL CYCLONES
IN THE SOUTHWEST INDIAN OCEAN
This feature is based in its entirety on an abstract for a poster
session intended for the AMS 25th Conference on Hurricanes and
Tropical Meteorology, held in San Diego, California, in April-May,
2002. The study was performed by Dr. Karl Hoarau of Cergy-Pontoise
University, Paris, France; Rene Robert of Reunion Island University,
France; and Jean Paul Hoarau, Reunion Island High School, France.
The abstract was submitted to the AMS conference committee and
appeared in the printed book of abstracts, but due to last-minute
exigencies, Karl was not able to get the poster ready to bring with
him to the conference. He has given me permission to include the
abstract as the feature in this month's tropical cyclone summary,
and I'd like to thank him for doing so.
The variations in the number of intense tropical cyclones (IC) with
maximum sustained (1-min avg) surface winds of 100 knots and more were
investigated over the past twenty-three seasons (1979-1980/2001-2002)
in the Southwest Indian Ocean west of 90E. The primary data sources
used in the analysis of the climatological characteristics of these ICs
were the "best track" data sets of the Joint Typhoon Warning Center
(JTWC), Meteo-France Reunion (MFR) and the Australian Bureau of
Meteorology (for the 80-90E area). The maximum intensity of tropical
cyclones was re-analyzed with the Dvorak method through the interpre-
tation of NOAA, DMSP and (since 1998) MeteoSat 5 satellite imagery.
A comparison shows that the re-analyzed data indicate more intense
cyclones, 73, than those obtained from MFR's data only (54) or from
JTWC's data only (67). This study revealed that an annual average of
three ICs formed in the Southwest Indian Ocean over the past twenty-
three seasons. The most impressive season in terms of strong cyclones
was 1994 with a peak of seven ICs. Another remarkable feature is that
the 1982-1983 and 1986-1987 El Nino seasons were accompanied by no
ICs, and only one storm reached the IC stage during the 1997-1998
El Nino. The re-analyzed number of ICs for the twenty-three year
period is as follows:
Season ICs Season ICs
----------------------------------------------------------------------
1979-1980 5 1991-1992 3
1980-1981 3 1992-1993 2
1981-1982 3 1993-1994 7
1982-1983 0 1994-1995 4
1983-1984 4 1995-1996 5
1984-1985 2 1996-1997 4
1985-1986 4 1997-1998 1
1986-1987 0 1998-1999 2
1987-1988 3 1999-2000 3
1988-1989 4 2000-2001 3
1989-1990 5 2001-2002 5
1990-1991 1
The number of ICs has increased in the 1990s, and this is especially
true for the extreme cyclones (120 knots or more) with a doubling of the
frequency when the previous decade, 1979-1980/1988-1989, is considered.
As the increase in frequency of stronger storms occurred before 1998--the
year in which good overhead geostationary satellite coverage of this
basin began with MeteoSat 5--the improved satellite imagery cannot be
used as the primary reason to explain this fact. The most intense
tropical cyclone observed in the Southwest Indian Ocean, and possibly
in the entire Southern Hemisphere, since 1979 was Tropical Cyclone
Geralda in late January, 1994, which attained a maximum sustained wind
estimated at 150 knots over one minute. (It now appears that the recent
Tropical Cyclone Zoe in the South Pacific basin has become the strongest
Southern Hemisphere tropical cyclone over the period under consideration
with a MSW estimated at 155 knots on 27 December 2002.)
The IC season lasts for six months--from November through April. The
monthly distribution of ICs shows that 15.1% occurred during the early
season (November and December), 49.3% during the mid-season (January
and February), and 35.6% during the late season (March and April).
Considering the extreme cyclones (at least 120 knots), the corresponding
percentages are 17.7%, 38.2%, and 44.1%. And the ratio of extreme
cyclones to all ICs is larger in December (based on a small sample)
and for the March-April period than in January or in February. At the
beginning and end of the season, the cyclones' tracks are more zonal
due to a stronger subtropical ridge during those months, so the storms
have a greater opportunity to intensify as long as they stay over warm
water and under the anticyclonic ridge, which provides a weak vertical
wind shear environment and good outflow. Also, another possible
explanation for the February lull in the most intense cyclones is that
the Intertropical Convergence Zone is normally at its most southerly
location during that month, and storms typically form at higher latitudes
and pursue more poleward tracks, taking them into cooler SSTs and higher
vertical shear environments more quickly.
The monthly distribution of intense tropical cyclones is as follows:
Month All ICs Peak 120+ kts Peak 130+ kts
-------------------------------------------------------------
November 6 2 1
December 5 4 3
January 18 8 5
February 18 5 0
March 14 7 4
April 12 7 2
Any person wishing to correspond with Karl regarding this paper may
reach him at the following address: KHoarau@aol.com
*************************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for December: No tropical cyclones
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for December: No tropical cyclones
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for December: 1 super typhoon
Sources of Information
----------------------
Most of the information presented below is based upon tropical
cyclone warnings and significant tropical weather outlooks issued
by the Joint Typhoon Warning Center of the U. S. Air Force and
Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion
tropical cyclone tracks file, I normally annotate track coordinates
from some of the various Asian warning centers when their center
positions differ from JTWC's by usually 40-50 nm or more. All
references to sustained winds imply a 1-minute averaging period
unless otherwise noted.
Michael V. Padua of Naga City in the Philippines, owner of the
Typhoon 2000 website, normally sends me cyclone tracks based upon
warnings issued by the Japanese Meteorological Agency (JMA) and the
Philippines' Atmospheric, Geophysical & Astronomical Services
Administration (PAGASA). Also, Huang Chunliang of Fuzhou City, China,
sends me each month tracks obtained from warnings issued by the
National Meteorological Center of China (NMCC), the Central Weather
Bureau of Taiwan (CWBT) and the Hong Kong Observatory (HKO). A very
special thanks to Michael and Chunliang for the assistance they so
reliably provide.
In the title line for each storm I have referenced all the cyclone
names/numbers I have available: JTWC's depression number, the
JMA-assigned name (if any), JMA's tropical storm numeric designator,
and PAGASA's name for systems forming in or passing through their
area of warning responsibility.
Northwest Pacific Tropical Activity for December
------------------------------------------------
The Northwest Pacific basin ended 2002 with a bang! The year's eighth
super typhoon (by JTWC's nomenclature) became the second typhoon of the
year to strike the island of Guam. (Earlier, in July, Typhoon Chataan
passed directly over the island as a Category 2 typhoon.) Even though
the exact center of Pongsona missed Guam, the western portion of the
eye passed over the island as the storm was reaching its peak intensity
of 130 kts. Damage assessments are not quite yet complete, but it is
likely that the total damage from Pongsona will equal or exceed that
caused by the destructive Typhoons Paka and Omar during the 1990s.
The summary for Super Typhoon Pongsona was written in part by Kevin
Boyle of Stoke-on-Trent, UK. A special thanks to Kevin for his help.
SUPER TYPHOON PONGSONA
(TC-31W / TY 0226)
2 - 10 December
------------------------------------------
Pongsona: contributed by North Korea, is the name of a type of tree
(the garden balsam)
A. Storm Origins
----------------
Pongsona's eventful career began as an area of convection located
near 5.0N, 163.5E (approximately 340 nm east-southeast of Pohnpei),
and was noted on JTWC's STWO issued at 0600 UTC, 30 November. At
this time, animated visible, multi-spectral and enhanced infrared
satellite imagery revealed an area of broad turning at lower and
mid-levels. QuikScat imagery indicated surface troughing in the area,
and a 200-mb analysis showed weak to moderate diffluence aloft with
weak to moderate vertical wind shear over the area. The potential for
tropical cyclone formation within the next 24 hours was assessed as
poor. This was upgraded to fair at 30/2200 UTC based on the development
of rainbands and better overall organization of the system, as seen on
microwave imagery.
Subsequent STWOs maintained the fair development potential, the
02/0600 UTC statement noting an elongated LLCC slightly decoupled to
the south of the deep convection. However, the system's organization
continued to improve, resulting in the issuance of a TCFA at 02/1100
UTC. The first warning on Tropical Depression 31W was issued at
02/1800 UTC (JMA had issued their first bulletin at 02/0600 UTC),
locating the centre near 7.4N, 163.5E, or approximately 215 nm southeast
of Ujelang Atoll. At this time the depression was tracking west-
northwestward at 6 kts with the MSW estimated at 25 kts. (JMA's 10-min
avg estimate was 30 kts.) The initial development stage was short, and
by the 2nd warning (03/0000 UTC) the system was upgraded to a 35-kt
tropical storm. However, animated multi-spectral satellite imagery
indicated that the LLCC was almost fully-exposed with the deep
convection located in the western quadrant.
B. Track and Intensity History
------------------------------
At 1200 UTC 3 December JMA upgraded the system to a tropical
storm (MSW 10-min avg) and assigned the name Pongsona. (At the same
time NMCC upgraded the system to tropical storm status and initiated
warnings.) JTWC had upped their MSW to 40 kts by this time, placing
the centre near 9.2N, 160.7E, or about 40 nm south-southeast of Ujelang
Atoll. The 04/0000 UTC warning relocated Pongsona about 60 nm to the
southwest of the 1800 UTC position. The storm subsequently began to
track westward on the 4th while slowly strengthening, reaching minimal
typhoon intensity at 05/0600 UTC (per JTWC). A 05/0356 UTC TRMM pass
revealed tightly-curved banding features and the possible formation of
an eyewall. In fact, BD curve enhancement revealed a developing, small
warm spot feature above the vortex. A mid-level ridge extending east-
ward from a HIGH centred over Luzon was basically keeping the cyclone on
a west to west-northwesterly track. Pongsona was forecast to turn north-
westward in response to a developing baroclinic LOW east of Japan.
(NMCC upgraded Pongsona to typhoon status at 05/1200 UTC and JMA followed
suit at 1800 UTC.)
Late on the 5th Pongsona was moving west-northwestward at 9 kts in
response to a shortwave trough passing over the northern Marianas. At
06/0000 UTC, the typhoon was positioned near 9.0N, 153.0E, or 125 nm
northeast of Chuuk, and the MSW had increased to 75 kts (CI 4.5). JTWC
issued an amended warning at 0300 UTC, stating that the position was
being relocated further west based on SSM/I data which revealed a
banding eye near 8.9N, 152.7E. However, the warm spot feature seen on
the 5th in BD enhancement imagery was not discernible at this time.
Pongsona continued to move westward at 9-10 kts, and this course had
changed to west-northwest, then into a northwesterly heading by 07/0000
UTC. Winds had strengthened to 95 kts by this time, and an SSM/I pass
revealed a cloud-filled irregular 20-nm diameter eye. A later SSM/I
pass at 07/0806 UTC and 07/0340 UTC TRMM imagery showed a larger 30-nm
eye located (at 07/1200 UTC) near 11.3N, 147.2E, or 185 nm southeast of
Guam. The baroclinic LOW had weakened the ridge, resulting in a more
northwesterly track, and another LOW was expected to force Pongsona
northward in the next 24 hours. The westward component in the track
would determine how close to Guam the centre would pass.
At 08/0000 UTC Pongsona began a period of rapid intensification,
and was still moving to the northwest as it began to bear down on Guam,
being centred only 75 nm to the southeast. Six hours later, the MSW had
reached 130-kt super typhoon intensity. The eyewall made landfall on
northeastern Guam at approximately 08/0500 UTC. The MSW on Guam was
estimated at 102 kts with peak gusts of 130 kts. The lowest pressure
reported from the National Weather Office was 940.4 mb. After leaving
Guam, the centre passed 15 nm west-southwest of Rota at 08/0700 UTC
with the island lying within the northern eyewall, and then approached
to within 80 nm of Tinian at 08/1100 UTC. Pongsona subsequently
passed about 75 nm west-southwest of Saipan at 08/1600 UTC.
Super Typhoon Pongsona had strengthened to its peak intensity
during the time it was battering Guam, and its course began to
change to a north-northwesterly heading. Peak intensities from JMA
and NMCC were 90 kts and 100 kts (10-min avg), respectively, on the
same day. SSM/I imagery depicted a well-developed eyewall and a
32-nm symmetric eye at 08/2030 UTC. Gales covered an area between
300 and 350 nm in diameter, and storm-force winds extended outward
an estimated 70 nm from the centre over water. The minimum central
pressure estimated by JMA was 940 mb.
By 09/0000 UTC the strength of the typhoon began to wane as the MSW
dropped to 125 kts, just below super typhoon strength. The intensity
had fallen further to 110 kts by 1800 UTC, and by 10/0000 UTC Pongsona
was accelerating northwards at 21 kts. Also, the cyclone was beginning
to interact with the mid-latitude LOW system moving eastward from Japan.
Notable effects were the weakening of deep convection in the southern
semicircle and dry air entrainment into the southwestern quadrant of
the system.
As Pongsona accelerated, it recurved to the east-northeast and the
maximum intensity fell below the 100-kt threshold at 10/1800 UTC.
A 10/1958 UTC SSM/I pass revealed that the LLCC was partially-exposed
with deep convection located to the east of the centre. Also, animated
water vapour imagery indicated increased dry air pouring into the system
from the north and west, while visible imagery showed a large mass of
stratocumulus clouds to the west, indicative of a more stable air
mass. Transition to an extratropical cyclone was considered nearly
complete at 11/0000 UTC and JTWC issued their final warning at this
time. The MSW estimate was 75 kts, and final centre fix was 27.1N,
156.0E, or approximately 750 nm northwest of Wake Island. JMA and NMCC
had the last word on Pongsona, both issuing their final warnings six
hours later. By 11/1800 UTC the remnant extratropical gale was located
approximately 750 nm west-northwest of Midway Island, this being the
final reference to it in JMA's High Seas Bulletins.
C. Meteorological Observations
------------------------------
Most wind sensors on Guam either failed or blew down during the
typhoon. According to Mark Lander, only one recorded the possible
peak conditions of the storm: a cup anemometer which reported a
maximum 2-min avg wind of 92 kts, equivalent to a 1-min avg MSW of
99 kts, at 6:26 pm (local time) near the height of the storm. Using
gust reduction ratios for open terrain exposure, potential peak
gusts in the 130-150 kt range are obtained. Mark, Chip Guard and
Art Chiu, a civil engineer from the University of Hawaii, have made
a wind assessment study for the NWS and official results are expected
to be released shortly. According to Chip, it is safe to say that
the peak 1-min avg MSW experienced on Guam was in the 120-130 kt
range and that the peak gusts were probably between 125 and 150 kts.
As for pressure, the minimum SLP readings across Guam ranged from
959 mb at the Naval Station on the west-central side of the island,
940 mb at the WFO at the airport in the central section of Guam,
and 937 mb at Andersen AFB on the northeastern side of the island.
Andersen AFB was in Pongsona's eye for over 1.5 hrs while the WFO
never entered the eye. Since the centre of the eye passed about
8 nm east-northeast of the AFB, a minimum CP of 935 mb is reasonable
and is being used as the CP of the cyclone at its closest approach
to Guam.
Torrential rains fell on Guam during Super Typhoon Pongsona's
visit. A dual tipping-bucket rain gauge at the University of Guam
(that was used in TRMM validation) recorded 167.1 mm in one hour,
390.9 mm in three hours, and 571.0 mm in six hours. A home rain
gauge at Windward Hills recorded 157.0 mm in one hour, 294.1 mm in
three hours, and 489.0 mm in six hours. For the 24-hour period
0000-2400 local time on 8 December, some amounts are:
University of Guam 650.5 mm
Windward Hills 510.8 mm
Andersen, AFB 525.3 mm
The Japanese island of Minamitori Shima (24.3N, 154.0E) recorded
a peak 10-min avg MSW of 36 kts and a minimum SLP of 1003.5 mb on
the 11th as Pongsona raced by shortly before becoming extratropical.
(Thanks to Huang Chunliang for sending me this bit of information.)
D. Damage and Casualties
------------------------
Super Typhoon Pongsona was very destructive to the island of Guam.
Damage typical of a severe Category 4 typhoon was observed: utilities
disrupted, many buildings damaged or destroyed, many trees blown down,
etc. According to Mark Lander, at the time of this writing the
overall damage assessment is not complete, but will almost certainly
exceed $500 million. By way of comparison, according to JTWC's Annual
Tropical Cyclone Reports, the damage to the island caused by 1992's
Typhoon Omar and 1997's Typhoon Paka was assessed at $457 million and
$600 million, respectively. (These tidbits of information from Jim
Leonard.) One death was directly attributed to the typhoon--an
elderly woman was cut badly during the height of the storm and went
into cardiac arrest.
There are many websites with information related to the aftermath
of Pongsona on Guam. A few located by the author are listed below.
Others may be found by using one of the internet search engines.
http://www.fema.gov/diz02/d1446n.shtm>
http://www.uog.edu/TyphoonPongsona/>
http://www.guampdn.com/news/stories/20021210/localnews/539486.html>
http://www.kuam.com/typhoons/pongsona/imagegallery.asp>
http://www.guampdn.com/guampublishing/pongsona/>
E. Discussion about Forecasts
-----------------------------
During the days following Typhoon Pongsona's strike on Guam, in
some of the press and media coverage there were allegations that Guam
did not receive adequate warnings of the impending typhoon nor of its
intensity. According to an e-mail from Roger Edson, the delegate from
Guam in the U. S. House of Representatives was calling for a federal
investigation of the typhoon warnings, claiming that Guam was never
informed that there was going to be a 'direct' hit or that the storm
was going to be 'super'.
Super Typhoon Pongsona made its closest point of approach (CPA) to
Guam around 0600 UTC on 8 December. Using an atlas and mileage scale,
I calculated the location of the northeasternmost tip of Guam to lie
very near 13.6N, 145.0E. The 08/0600 UTC position based on the
warning was 13.5N, 145.2E, or about 13 nm east-northeast of the afore-
mentioned point, which in my atlas is labeled Point Pati. I examined
all the JTWC warnings beginning at 0600 UTC on 5 December--72 hours
prior to the typhoon's CPA to Guam--and calculated the "miss distance"
to Point Pati for the various forecast times. The results are
tabulated below:
Date/Time Hours Lat Lon Fcst MSW Fcst Distance (nm)
(UTC) to CPA (kts) and Direction
---------------------------------------------------------------------
05/0600 72 14.4 N 145.7 E 105 63 to NE
06/0600 48 14.8 N 146.7 E 105 123 to NE
06/1800 36 14.1 N 146.6 E 105 98 to ENE
07/0600 24 14.4 N 145.7 E 110 63 to NE
07/1800 12 13.4 N 145.1 E 115 13 to SSE
In terms of the forecast errors--the distance between the actual
08/0600 UTC position and the forecast position at that hour for
various lead times--the results are:
72 hours - 62 nm
48 hours - 117 nm
36 hours - 89 nm
24 hours - 62 nm
12 hours - 8 nm
Based on statistics gleaned from JTWC's Annual Tropical Cyclone Report
for 2001, over the 10 seasons 1992-2001, the average forecast errors for
storms of typhoon intensity (when the MSW was 35 kts or greater at the
time the forecast was issued) are:
72 hours - 267 nm
48 hours - 175 nm
24 hours - 93 nm
So, as can be seen by comparing the average forecast errors with the
corresponding Pongsona forecasts, the forecast errors for Pongsona
(relative to its CPA to Guam) were well below the average error,
especially the 72-hour forecast--62 nm is outstanding. According
to an e-mail from Roger Edson, the official 72-hour forecast error
for the 2002 season is 162 nm, so the 72-hour forecast for Typhoon
Pongsona was well under the average for the season.
So why, then, the allegations that the forecast wasn't adequate?
Probably in part due to the unrealistic expectations that the public
often has that a strike by an impending cyclone should be forecast
with pinpoint accuracy--something which just isn't possible. But one
aspect of the forecasts, however, possibly did help to engender a
sense of complacency. That was the fact that the 48 and 24-hour
forecasts called for a considerably larger miss distance than had
the 72-hour forecast. So, three days in advance of Pongsona's visit
to Guam, it looked like a severe Category 3 typhoon would make a
fairly close approach, but still remain a "safe" distance to the
east such that the island would be expected to miss the inner
intense core. Then, over the succeeding days, it appeared that
Pongsona would miss the island by an even larger margin. I know for
a fact that this change in the predicted track between the 72-hour and
48-hour forecasts were enough to cause a well-known storm chaser to
cancel his plans to fly to Guam to intercept Pongsona.
An earlier e-mail from Roger Edson indicated that the Congressional
delegate from Guam had raised the question of whether having
aircraft reconnaissance would have improved the timeliness of the
forecasts. Ostensibly, the JTWC forecasts were basically following
the general consensus of the numerical model guidance. Simply having
center fixes by an aircraft may or may not have had much impact upon
the forecasts; having the storm's environment extensively sampled as
is often done by the NOAA research plane in the western Atlantic
possibly might have yielded some clues that would have given earlier
indications that the typhoon would strike Guam.
The bottom line is that tropical cyclone track and intensity fore-
casting is by no means an exact science, and the public (and media)
of all cyclone-prone countries need to be constantly reminded of this
fact. Pongsona serves as an excellent illustration of the old adage
to "always expect the unexpected" when dealing with tropical cyclones.
(Sections A and B of this report were written by Kevin Boyle and
Sections C, D and E were written by Gary Padgett)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for December: 1 tropical cyclone of gale intensity
Sources of Information
----------------------
Most of the information presented below is based upon tropical
cyclone warnings and significant tropical weather outlooks issued
by the Joint Typhoon Warning Center of the U. S. Air Force and
Navy (JTWC), located at Pearl Harbor, Hawaii. Occasionally some
information may be gleaned from the daily tropical weather outlooks
and other bulletins issued by the Indian Meteorological Department
(IMD), which is the World Meteorological Organization's Regional
Specialised Meteorological Centre (RSMC) for the basin.
The reported maximum sustained winds (MSW) are based on a 1-minute
averaging period, which is used by all U. S. civilian and military
weather services for tropical cyclone warnings. For synoptic
observations in the North Indian Ocean region, both 10-minute and
3-minute average winds are employed, but IMD makes no attempt to
modify the Dvorak scale for estimating tropical cyclone intensity;
hence, a 1-minute average MSW is implied. In the North Indian Ocean
basin JTWC usually does not initiate warnings until a system has
become well-organized and likely to attain tropical storm status
within 48 hours.
The summary for Tropical Cyclone 05B was written by John Wallace of
San Antonio, Texas. A special thanks to John for his assistance.
TROPICAL CYCLONE
(TC-05B)
22 - 25 December
------------------------------------
The LOW that became TC-05B developed within the ITCZ south of Sri
Lanka on 20 December and tracked slowly east-northeastward over the
following two days. The disturbance slowly consolidated, and the JTWC
issued a TCFA at 1251 UTC on 22 December when the system was located
roughly 235 nm south-southeast of Sri Lanka.
The LOW organized further as it traveled northeastward, and the JTWC
issued their first advisory on Tropical Cyclone 05B as a minimal tropical
storm at 1800 UTC on 23 December when it was located 85 nm southeast of
Dondra Head, Sri Lanka. The initial warning MSW of 35 kts, with an
estimated CP of 997 mb*, proved to be its "peak" intensity as it tracked
northeastward. Never very impressive, its convection inexplicably
collapsed on the 25th, possibly due to interference from another cyclonic
disturbance to the south. The JTWC issued the final warning at 1800 UTC
on 25 December with the center located about 370 nm east-northeast of
Dondra Head. (* See the November summary write-up of TC-03B for an
explanation of the determination of the CP estimate.)
Editor's Note: This system appeared quite well-organized a couple of
days prior to JTWC's initiating warnings. SAB assigned a Dvorak rating
of T2.5/2.5 (35 kts) as early as 2030 UTC on 22 December, and had upped
the intensity to 55 kts (T3.5) by 23/1430 UTC, still prior to JTWC's
first warning.
No casualties or other damages are known to have resulted from this
minimal tropical cyclone.
(Report written by John Wallace)
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for December: 1 tropical depression
1 severe tropical storm
1 tropical cyclone (hurricane)
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Southwest Indian Ocean tropical cyclones are the warnings issued by
the Tropical Cyclone Warning Centre on La Reunion Island, part of
Meteo France (MFR), and the Regional Specialised Meteorological Centre
for the basin. However, tropical cyclones in this region are named
by the sub-regional warning centres on Mauritius and Madagascar with
longitude 55E being the demarcation line between their respective
areas of warning responsibility. The La Reunion centre only advises
these agencies regarding the intensity of tropical systems. References
to sustained winds imply a 10-minute averaging period unless otherwise
stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from MFR's coordinates by usually
40-50 nm or more. The JTWC warnings are also the source of the
1-minute average maximum sustained wind values included in the
tracks file. Additionally, information describing details of
satellite imagery and atmospheric circulation features included in
the narratives is often gleaned from the JTWC warnings.
Southwest Indian Ocean Tropical Activity for December
-----------------------------------------------------
After lying quiet for the first three weeks of December, the tropics
suddenly woke up in the Southwest Indian Ocean during the final third
of the month. Tropical Cyclone Crystal became a hurricane of moderate
intensity as it passed only about 100 nm east of Mauritius. Crystal had
initially posed a serious threat to the island, but remained far enough
offshore as it tracked southward that peak wind gusts remained well
below hurricane force. During the final days of the year, short-lived
Severe Tropical Storm Delfina popped up in the Mozambique Channel and
moved westward into Mozambique. The storm's torrential rains led to
severe flooding and significant loss of life.
The only other system in the basin during December was a tropical
depression numbered as Tropical Depression 05 by MFR and as Tropical
Cyclone 07S by JTWC. The system formed on the 25th approximately
725 nm west-northwest of the Cocos Islands. Over the next few days it
drifted southward, turning eastward on the 27th and entering Perth's
AOR. The peak sustained wind estimated by JTWC and MFR was 30 kts, and
Perth never issued any gale warnings on the system. The LOW drifted
around erratically, and JTWC issued their final warning at 1800 UTC
on 28 December when the center was located about 250 nm west-northwest
of the Cocos Islands. Perth continued to refer to the slowly weakening
system in their daily Tropical Weather Outlooks through 4 January.
Much of the report on Tropical Cyclone Crystal was written by Thomas
Birger, a weather enthusiast and student who lives in Mauritius. A
special thanks to Thomas for his assistance.
TROPICAL CYCLONE CRYSTAL
(MFR-04 / TC-05S)
22 - 30 December
--------------------------------------------
Crystal: contributed by Mauritius
A. Storm Origins
----------------
After lying quiet for a month following a very active first part of
November, the Southwest Indian Ocean basin re-awakened during the second
half of December in a manner similar to the previous season. (The 2001-
2002 season came alive even earlier than the current one: in October
a tropical depression formed early in the month, followed by Tropical
Storm Alex-Andre late in the month. Another tropical depression in mid-
November was followed by Tropical Cyclone Bessi-Bako in late November/
early December. However, the region lay quiet then for almost a month
until Tropical Storm Cyprien came to life late in December.) The Madden-
Julian Oscillation (MJO) had been unfavourable for any important
convective activity in this region since the end of November, 2002. As
from the 18th of December, many models were announcing a new active
period. The GFS, ECMWF, EMC and the UKMET model were forecasting cyclo-
genesis south and west of Diego Garcia with the system taking a track
that could mean serious business for Mauritius just after Christmas.
This forecast soon began to verify. On the morning of 22 December,
JTWC re-issued its daily STWO, adding an area of convection which had
developed near 7.5S, 69.5E, or approximately 145 nm west of Diego Garcia.
MFR issued its first warning also for this fourth disturbance of the
season a few hours later, at 1200 UTC. MFR positioned the disturbance
(1004 hPa) near 8.2S, 68.3E, and analysed a westward motion at 5 kts.
During the afternoon and the first part of the night, the disturbance
did not intensify significantly and became stationary. MFR upgraded the
disturbance to a tropical depression on the morning of 23 December and
placed the center near 10.2S, 66.9E, at 0600 UTC, or about 375 nm west-
southwest of Diego Garcia. The MSW (10-min avg) was estimated at 30 kts
with a CP of 996 hPa, and the system was then moving west-southwestward
at 6 kts.
B. Track and Intensity History
------------------------------
The Mauritius TCWC named the system Crystal at 1200 UTC on the 23rd
with the CP estimated to have dropped to 994 hPa. JTWC also initiated
warnings on Crystal at the same time, estimating the MSW (1-min avg)
at 35 kts, the same value as MFR's 10-min avg MSW. Crystal was centred
near 11.2S, 66.6E, or roughly 425 nm west-southwest of Diego Garcia.
JTWC was indicating a southwesterly track, and forecast that this would
be the general trend for the next few days as the moderate tropical storm
tracked along a low to mid-level ridge located to the southeast. Crystal
in fact tracked southwestward during the 24th, but occasionally tended to
move a little more west-southwestward, becoming a real threat to
Mauritius as the island was situated directly in its path. Newspapers
in Mauritius published on their front pages: "A Possible Direct Threat
for Mauritius on Thursday." Crystal continued to intensify--MFR upped
the MSW to 50 kts at 24/0600 UTC while JTWC increased their 1-min avg
MSW estimate to 55 kts at 1200 UTC (based on a CI estimate of 3.5).
The JTWC warning remarked that recent microwave data had revealed some
dry air entraining into the storm from the west. Based on MFR's
position, Crystal's centre at 1200 UTC was located about 240 nm north-
east of the island of St. Brandon while JTWC located the centre about
38 nm northeast of MFR's position.
Both MFR and JTWC upped their respective MSW estimates to 65 kts at
0000 UTC on Christmas Day. A 24/2203 UTC AMSU pass had depicted a
developing banding eye feature. At 25/1200 UTC JTWC further increased
the intensity to 75 kts (based on CI estimates of 65 and 77 kts), but
MFR lowered the MSW (10-min avg) to 60 kts. The banding eye was still
evident, but the dry air entraining into Crystal from the west had eroded
the deep convection in the eastern quadrant. Satellite CI estimates (as
reported by JTWC) remained at 65 and 77 kts through the 26th, but JTWC
decreased the 1-min avg MSW to 70 kts at 26/0000 UTC. The guidance
models were in agreement on the cyclone's direction of movement for the
next several days. Mauritius was apparently no longer in danger. On the
25th JTWC's warning remarked that a longwave trough over the southern
portion of the Mozambique Channel was expected to deepen and propagate
eastward by the 27th, weakening the subtropical ridge to the south of
Crystal.
On 26 December Crystal's motion became south-southwesterly. The
storm passed quite close to St. Brandon (approximately 30 nm to the
southeast). Gusts did not exceed 49 kts with a minimum SLP of 997-998
hPa. By 1200 UTC the dry air entrainment had lessened and the banding
eye was more prominent. Surprisingly, Crystal intensified rapidly
during the night, which was not forecast, and reached its peak intensity
(90 kts from JTWC) while passing to the east of Mauritius. By 0000 UTC
on the 27th, Crystal had become a more symmetrical system with a ragged
eye visible. MFR upped their 10-min avg MSW estimate to the peak of
75 kts at 27/0600 UTC with the minimum CP estimated at 956 mb. The
cyclone remained at this peak for 18 hours per MFR, whereas JTWC lowered
the intensity to 80 kts at 27/1200 UTC. Satellite CI estimates were
still 77 and 90 kts, but the eyewall had begun to weaken in all
quadrants. There was some disagreement between JTWC and the Mauritius
TCWC as to Crystal's nearest approach to the island. JTWC placed the
centre 118 nm east of the island at 27/0000 UTC, whereas Mauritius
had it closer (90 nm from the eastern coast). (However, it seems quite
likely that JTWC was using a coordinate near the centre of the island
for its reference point). In any event, the most intense portion of the
cyclone remained well east of the island, and Mauritius did not
experience any winds of cyclone (i.e., hurricane) force. Cyclones
passing to the east of an island in the Southwest Indian Ocean are
usually "dry", and also do not expose the island to their highest winds.
By 28/0000 UTC Crystal had begun to track to the south-southeast.
MFR lowered the intensity to 70 kts, and the JTWC warning noted that the
eye feature was no longer evident and the system was in the first stages
of extratropical transition. The storm's centre was then located about
280 nm southeast of Mauritius, and by 1200 UTC was approximately 385 nm
southeast of Reunion Island. JTWC was still estimating the 1-min avg
MSW at 70 kts (based on CI estimates of 77 kts), but MFR had lowered the
intensity to 55 kts. Recent microwave imagery indicated that the LLCC
had become partially-exposed with the deepest convection to the southeast
of the centre, and increased dry air entrainment was also apparent. JTWC
analysed the system as extratropical at 29/0000 UTC and issued their
final warning. Crystal continued to move steadily southeastward, and
MFR declared the system extratropical at 1800 UTC. The extratropical
depression continued southeastward with winds weakening below gale
force by 30/1200 UTC.
C. Meteorological Observations
------------------------------
Mauritius was under cyclone alert #2 (out of 4) from the 26th to the
27th of December. The highest gusts recorded include 49 kts at Bain
Boeuf station in the northern part of the island early on the 27th,
43 kts at Queen Victoria station in the eastern part of Mauritius, and
39 kts at Trou-aux-Cerfs and Grand-Bassin stations on higher terrain
in the middle of the island. Thomas Birger (the principal author of
this report) recorded a minimum pressure of 1002 hPa in the north of
Mauritius at 0200 UTC on the 27th.
The following rainfall totals were recorded during the 24 hours
ending at 0600 UTC on 27 December:
Providence 58.8 mm
Nouvelle-Decouverte 58.2 mm
Trou-aux-Cerfs 50.6 mm
Vacoas 49.3 mm
Mon Bois 44.0 mm
Almost no rain fell in the northern portion of Mauritius.
D. Damage and Casualties
------------------------
No reports of damage or casualties resulting from Tropical Cyclone
Crystal have been received by the author. However, wind gusts in the
40-50 kt range such as were experienced on Mauritius could have caused
some scattered, minor damage to vegetation and weaker structures.
(Report written by Thomas Birger with additions and editing by
Gary Padgett)
TROPICAL STORM DELFINA
(MFR-06 / TC-08S)
30 December - 1 January
-------------------------------------------
Delfina: contributed by Mozambique
A. Storm History
----------------
JTWC re-issued the daily STWO for the Southwest Indian Ocean at 1100
UTC on 30 December, noting that an area of convection approximately 65 nm
west of Madagascar in the Mozambique Channel had persisted for over
twelve hours. Animated multi-spectral imagery and a 30/0505 UTC SSM/I
pass revealed a weak LLCC with associated cycling deep convection, while
an upper-air analysis indicated good diffluence and weak vertical shear.
The STWO was re-issued only an hour later and the development potential
upgraded to fair--deep convection had become more persistent and the
LLCC better defined. At the same time (1200 UTC) MFR initiated warnings
on the disturbance--the sixth of the SWI season.
JTWC issued their first warning on TC-08S at 1800 UTC, locating the
center in the Channel about 140 nm off the coast of Mozambique, moving
west-southwestward at 5 kts. The MSW (1-min avg) was estimated at
35 kts, and recent microwave imagery depicted increasing organization
while animated infrared imagery revealed favorable poleward outflow.
At 0600 UTC on 31 December the center of the system was only about 70 nm
east of Mozambique and moving westward at 5 kts. Significant deep
convection had developed near the center and several rainbands were
evident. At the same time, MFR upgraded the system to tropical
depression status with 30-kt winds (10-min avg).
At 1200 UTC Tropical Storm Delfina was christened with the intensity
set at 40 kts. The system intensified rather quickly as it approached
the coast of Mozambique. The center was almost on the coast at 1800
UTC. MFR and JTWC estimated the MSW at 50 kts and 55 kts, respectively,
based on a CI-number of 3.5, plus a 31/1725 UTC SSM/I pass which depicted
the development of a possible eye feature. The center of Tropical Storm
Delfina made landfall near Angoche, Mozambique, at approximately 2030 UTC
and quickly began to weaken. MFR issued their final warning at 0000 UTC
on 1 January, 2003. Winds near the center were weakening, but gales of
up to 45 kts were still forecast over seas in the southeastern semi-
circle. JTWC issued their final warning at 01/0600 UTC, placing the
center of Delfina about 165 km inland and moving west-northwestward at
6 kts.
B. Damage and Casualties
------------------------
Delfina moved inland as a severe tropical storm, but it was the
storm's rainfall which wreaked havoc in Mozambique. Heavy rains fell
over the northern portion of the nation--the northern province of
Nampula being especially hard-hit. Nampula City recorded 281 mm of
rain on 4-5 January. The number of fatalities directly attributed to the
flooding is somewhat difficult to assess--reports dated late in January
indicate that between 9 and 19 persons died. There were also deaths due
to disease outbreaks in the aftermath of the floods. There had been
45 deaths due to malaria in northern Mozambique by late in the month,
and 12 persons had died from cholera.
In Nampula Province between 18,000 and 20,000 houses were either
partially or totally destroyed, rendering some 100,000 persons homeless.
Between 2000 and 3000 hectares of crops (beans and cassava) as well as
thousands of cashew nut trees were washed away, and many livestock were
lost. The heavy rains damaged water supply systems in urban centers,
and more than 350 schools were destroyed. There was also damage to
roads, highways, bridges, and electrical power lines. Many areas became
isolated at a time when food stocks had been depleted due to drought and
a disease affecting the cassava crop.
Zambezia Province was also affected by the flooding with 1800 persons
displaced. The neighboring country of Malawi was also adversely
affected with eight deaths confirmed and 15,000 persons left homeless.
More information on the aftermath of Tropical Storm Delfina's flooding
can be found at the following URL:
http://www.reliefweb.int/w/rwb.nsf/vLND>
(Report written by Gary Padgett)
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for December: 1 tropical LOW **
** - system formed west of 90E and moved westward into Perth's AOR
Northwest Australia/Southeast Indian Ocean
Tropical Activity for December
------------------------------------------
No tropical cyclones formed in the Southern Hemisphere between 135E
and 90E during December. A tropical depression formed on 25 December
east of 90E and moved into Perth's AOR on the 27th. (This depression
had been designated as Tropical Depression 05 by MFR and as Tropical
Cyclone 07S by JTWC.) The system initially had some potential for
intensification, but never strengthened above the depression stage.
Perth monitored the LOW for several days in the Tropical Weather Out-
looks, but no gale warnings were ever issued. (More information on
this system can be found in the section of this summary covering the
Southwest Indian Ocean basin.)
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for December: No tropical cyclones
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for December: 1 tropical depression
1 tropical cyclone of gale intensity
1 tropical cyclone of hurricane intensity
Sources of Information
----------------------
The primary sources of tracking and intensity information for
South Pacific tropical cyclones are the warnings and advisories
issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
waters north of latitude 25S), and Wellington, New Zealand (for
waters south of latitude 25S). References to sustained winds imply
a 10-minute averaging period unless otherwise stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from the Southern Hemisphere
centres' coordinates by usually 40-50 nm or more. The JTWC warnings
are also the source of the 1-minute average maximum sustained wind
values included in the tracks file. Additionally, information
describing details of satellite imagery and atmospheric circulation
features included in the narratives is often gleaned from the JTWC
warnings.
South Pacific Tropical Activity for December
--------------------------------------------
A tropical depression which had formed in late November persisted for
several days and eventually developed into weak Tropical Cyclone Yolande
on the 4th, well southeast of Fiji. Yolande's life as a tropical
cyclone was brief--only 13 hours after it was named it had weakened into
an extratropical depression. Another system during the second week of
the month was designated as Tropical Depression 03F by Fiji. This system
formed on the 10th about 350 nm east-northeast of American Samoa. The
depression was broad and diffuse and difficult to track, with the center
position being relocated several times. On 13 December the center was
relocated much farther to the west to a point about 100 nm south-
southwest of Pago Pago. The LOW was weakening even then, and was dropped
from Nadi's Tropical Disturbance Summaries on the 15th when located just
south of Fiji. It was briefly mentioned again as a weak disturbance on
the 19th and 20th when located west of Fiji. Peak winds in this system
likely did not exceed 30 kts.
The really big story of the month was the extremely intense Tropical
Cyclone Zoe during the final week. Zoe became one of the strongest
tropical cyclones seen in the South Pacific basin since the advent of the
satellite era. Both JTWC and Nadi assessed the cyclone at a solid T7.5
on the Dvorak scale, with Nadi estimating the peak 10-min avg MSW at
130 kts and JTWC reporting the peak 1-min avg MSW at 155 kts. The
monstrous cyclone stalled and described a small loop near the tiny
islands of Anuta and Tikopia in the Solomons while it was at its peak
intensity. The result was near-complete devastation of the vegetation
and buildings on the small islands. However, the inhabitants took
refuge in rocky overhangs on higher ground and there were no fatalities
and few serious injuries.
The reports on Tropical Cyclones Yolande and Zoe were largely written
by Simon Clarke of Cleveland, Queensland, Australia, and with some
information obtained from storm reports prepared by Alipate Waqaicelua,
Chief Forecaster at the Tropical Cyclone Warning Centre at Nadi, Fiji.
A special thanks to Simon and Alipate for their assistance.
TROPICAL CYCLONE YOLANDE
(TD-02F / TC-04P)
29 November - 6 December
--------------------------------------------
Tropical Cyclone Yolande, the first cyclone to be named by the Fiji
Meteorological Office since Tropical Cyclone Waka almost twelve months
prior, was a short-lived system in terms of tropical cyclone status.
The initial depression formed from a broad area of thunderstorm activity
stretching north and westward across the equator. Of note, this area of
convection was ultimately to produce Typhoon Pongsona in the Northern
Hemisphere (refer to separate report).
The tropical depression (TD-02F) that ultimately developed into
Yolande was first noted at 2337 UTC, 29 November 2002, over Southern
Tuvalu as a 999 hPa low embedded in an active monsoon trough. The LOW
was moving slowly south-eastward with convection displaced to the east
and north of the low-level circulation. Sea surface temperatures at
the time were 30 degrees C with the strongest winds confined to the
northeastern half of the circulation.
This general trend was to continue with diurnal fluctuations in
intensity and structure whilst TD-02F continued to move into an area of
decreasing vertical wind shear. The first gale warning was issued by
RSMC Nadi at December 03/1918 UTC as the depression edged generally
toward the south or south-southeast at 5 kts. By 03/1824 UTC TD-02F
was located near 16S, 178W, and Tropical Disturbance Advisory Number A1
was issued from RSMC NADI. Convective organisation was improving with
outflow potential in all quadrants good. Slow deepening in central
pressure was to follow, and at December 04/2300 UTC Yolande was finally
named. At this time the storm was located near 20.4S, 174.7W, (about
90 nautical miles east of Nukualofa, the Capital of Tonga) and had a
central pressure reading of 995 hPa. Movement was to the southeast
at 10 kts with gradually increasing forward speed.
Within 8 hours of naming, Yolande had drifted into an area of moderate
to strong vertical northwest wind shear with its centre exposed some
80 nautical miles to the northwest of the deepest convection. Extra-
tropical transition had commenced and Tropical Cyclone Yolande was down-
graded to depression status at 05/1343 UTC while located near 21.8S,
172.2W. The remnant LOW was observed to track generally toward the
southeast over the next few days, leaving an extensive convergence zone
to its north.
Editor's Note: The highest MSW (10-min avg) assigned by Fiji was 35 kts.
JTWC issued only two warnings on Yolande, with the highest 1-min avg
MSW estimated at 40 kts on the initial warning.
Yolande spent its entire life at sea and no damage is known to have
resulted.
(Report written by Simon Clarke with contributions by Alipate Waqaicelua,
Chief Forecaster at the Nadi TCWC)
TROPICAL CYCLONE ZOE
(TD-04F / TC-06P)
23 December - 1 January
-------------------------------------------
A. Storm Origins
----------------
Tropical Cyclone Zoe was one of the most intense cyclones ever seen in
the Southern Pacific Ocean. Zoe was the second tropical cyclone of the
2002/2003 South Pacific Tropical Cyclone Season. The cyclone formed to
the north of Rotuma and moved steadily westwards, undergoing rapid
intensification. It passed close to the islands of the Temotu Province
(Solomon Islands) before turning southeast and passing about 180 nautical
miles to the west of Fiji. Tropical Cyclone Zoe had a total life span
of seven days and a peak intensity of about 130 kts (10-minute average).
A Tropical Depression (TD-04F) was first identified within the South
Pacific Convergence Zone about 360 nm to the east of Funafuti in Tuvalu
around December 23/2100 UTC 2002. The depression generally moved west-
southwestward while developing slowly. RSMC Nadi issued the first
Tropical Disturbance advisory at 25/1933 UTC when the depression was
located (at 1800 UTC) near 11.3S, 177.3E, and showing improving
organisation with good poleward outflow. Convection increased along the
western and northwestern edges, forming a greater banding pattern as the
depression was situated under an area of upper diffluence. The system
continued to track toward the west-southwest, being steered by the
northern end of a low to mid-level subtropical ridge.
Around 25/0900 UTC, TD-04F was located about 130 nautical miles to
the north-northeast of Rotuma and still drifting west-southwestward.
During the night, convection erupted over the low-level central
circulation and rapidly cooled. Spiral banding curvature increased
markedly while wrapping tightly around the centre. Outflow over the
system also improved greatly as vertical wind shear decreased
significantly over and downwind of the depression. At 25/2100 UTC the
depression was upgraded to tropical cyclone status and code named Zoe.
At this stage, Zoe was located about 120 nautical miles to the northwest
of Rotuma and moving westward at about 10 kts.
B. Track and Intensity History
------------------------------
Zoe intensified very rapidly under a favourable environment of
decreasing upper shear, exhibiting good outflow in all quadrants, whilst
being steered to the west at 10 kts by a mid-level subtropical ridge to
the south. Zoe continued to develop rapidly with an eye appearing on
27 December. (RSMC Nadi upgraded Zoe to hurricane intensity with 75-kt
winds at 27/0000 UTC.) The cyclone turned towards the southwest, passing
between the islands of Anuta and Fataka.
In the 54 hours between 26/0155 UTC and 28/0831 UTC, Zoe's central
pressure fell approximately 100 hpa (990 hPa to 890 hPa), reaching a
peak intensity of 130 kts. At the end of this period Zoe commenced a
small clockwise loop and remained slow-moving between December 28/0600
UTC and 29/0000 UTC, completing the loop adjacent to the island of
Tikopia. Following this general stall in motion, Zoe embarked on a
track to the southeast in response to a westward-approaching upper-trough
to the south.
Zoe also began to rapidly weaken, disintegrating under strengthening
shear, dry air entrainment (evident in the western sector), and cooler
sea surface temperatures as it continued on its southeasterly track.
The storm passed about 180 nautical miles to the west of Nadi (Fiji)
around 31/0600 UTC. At 0000 UTC on 1 January, 2003, Zoe was downgraded
to a tropical depression when it was located about 210 nautical miles
to the southwest of Nadi. The remnant depression ultimately turned
toward the south and then southwest in accordance with the deep-layer
mean wind flow prior to dissipation.
The following is an extract from the WeatherZone by Brisbane
meteorologist Jonty Hall: "It is important to note that the central
pressure of Zoe was not directly observed, but estimated from satellite
imagery using the Dvorak analysis and is subject to some degree of
error."
Editor's Note: JTWC assigned a peak 1-min avg MSW of 155 kts at 27/1200
and 28/0000 UTC. This was based on a Dvorak rating of T7.5. Fiji's
peak 10-min avg MSW, as noted above, was 130 kts. This was based also
on a T-number of 7.5, but being slightly more conservative. (Using the
widely accepted 1-minute to 10-minute conversion factor of 0.88, 155 kts
1-min avg equals 136 kts 10-min avg.)
C. Damage and Casualties
------------------------
Zoe's main impact was to the islands of Fataka, Anuta and Tikopia
(all in the Temotu Province) with severe damage to vegetation and infra-
structure. Fataka Island is uninhabited, while Anuta and Tikopia
collectively have a population of approximately 3,700 residents.
Zoe's peak on 28 December 2002 was accompanied by extremely high seas
and a 5 to 10 metre storm surge, sustained winds of 133 kts (10-min avg)
and gusts up to 185 kts. At this time the eye of the storm was located
only 50 km southeast of Anuta. Over the next 24 hours, Zoe moved very
little while maintaining its intensity as it passed within 30 km of
Tikopia. Tikopia was to endure more damage than Anuta with the storm
washing away most of the coastal villages and food crops on the island.
Tikopia's partially-piped water supply systems were severely damaged with
the reservoir tank smashed and pipes broken and displaced. There is,
however, a good quality fresh water source from a spring on the beach,
although it is only accessible at low tide. Damage on Anuta was
considerably less with the majority of dwellings remaining intact and
with less damage to vegetation. Communications to both islands were
severed for a week.
The following is an excerpt of a report from New Zealand storm and
natural disaster chaser Geoff Mackley: "I have just flown over Tikopia
Island at 0900 on January 1 and the island is a scene of total
devastation. In my experience with severe weather the maximum winds
on the island would have been between 300 and 350 km/hr (165-190 kts).
Tikopia Island would have been in the eyewall of Cyclone Zoe when it
was at its peak strength--every tree on the island has been blown over
or shredded, the island is completely denuded of vegetation, almost
every building has been damaged--a few remain intact while others have
been shredded, and the sea has come through some villages, burying
them. This sort of destruction is normally seen only after a strong
tornado or volcanic eruption. A number of people, maybe 20, came down
to the beach to watch us fly over. Some signaled us with sheets of
white plastic; others just sat there. We were unable to land as the
the island has no airstrip. I will not speculate on the likely
casualties or fatalities--if it is not large it will be a miracle."
The "miracle" alluded to by Geoff apparently happened--despite the
incredible destruction inflicted by the storm, no deaths or major
injuries have been directly attributed to Zoe, with residents reported
to have taken refuge inland on higher ground under over-hanging rocks.
These were not caves, and they became increasingly exposed as the wind
stripped the surrounding ground cover. Certain diseases, including
diarrhea, septic infections and boils, increased significantly following
the cyclone's passage.
The long-lasting after effects of Zoe are quite appalling. The
majority of buildings on Tikopia are traditional structures constructed
with local materials. The normal life of a sago palm thatched roof is
just two years; therefore, all surviving structures on the island will
need new roofs within the next 12-18 months. All traditional housing
material on the island has been lost. It will take from 6-12 years for
sago palms to regenerate and even longer for structural timer. Tikopia
will therefore not be able to approach self-sufficiency in building
materials for at least 12 years.
Agricultural productivity on the island has been totally wiped out.
All gardens on the hill slopes were destroyed by high winds, sand and
salt spray while those on lower ground were affected by wind and/or storm
surge. Large fruit trees such as local avocado and breadfruit have
been stripped and broken--any that survive will not produce fruit for
2 or 3 years. The cyclone's winds and rain stripped the ground of
vegetation, humus and topsoil, leaving it dry, hard, exposed and unsuit-
able for planting. It will likely take 2-3 years for taro to become
available and in excess of 5 years for coconuts. With the exception
of one small patch of relatively intact vegetation on a westward-facing
hill slope, there is no 'greenery' left on the island. A freshwater
lake contained four species of fish which provided a reliable food
source, but saltwater inundation of the lake along with filling from
debris, swamp mud and sand means that these fish will not survive.
Even if the lake becomes relatively fresh again over the next 12-18
months, restocking from other islands will be necessary.
In Vanuatu, some islands in the northern parts of the country
experienced seawater inundation. However, a survey by French Military
personnel found that there were no fatalities on the islands of Mota
Lava. In Fiji, no damage was reported.
Many articles relating to the destruction wrought by Tropical Cyclone
Zoe can be found at the following URL:
http://www.reliefweb.int/w/rwb.nsf/vLND>
Geoff Mackley has many pictures from Tikopia available on his website:
http://www.rambocam.com/zoe.html>
A special thanks to Jeff Callaghan for sending me a damage assessment
report prepared by Dr. Linda Anderson-Berry of the James Cook University
Centre for Disaster Studies. Dr. Anderson-Berry led a team to Tikopia
and Anuta shortly after the cyclone's passage and prepared an extensive
and interesting field assessment report. A considerable portion of the
information presented in Section C was obtained from this report.
(Report written by Simon Clarke and Gary Padgett with contributions by
Alipate Waqaicelua, Chief Forecaster at the Nadi TCWC)
*************************************************************************
EXTRA FEATURE
In order to shorten the amount of typing in preparing the narrative
material, I have been in the habit of freely using abbreviations and
acronyms. I have tried to define most of these with the first usage
in a given summary, but I may have missed one now and then. Most of
these are probably understood by a majority of readers but perhaps a
few aren't clear to some. To remedy this I developed a Glossary of
Abbreviations and Acronyms which I first included in the July, 1998
summary. I don't normally include the Glossary in most months in
order to help keep them from being too long. If anyone would like to
receive a copy of the Glossary, please e-mail me and I'll be happy
to send them a copy.
*************************************************************************
AUTHOR'S NOTE: This summary should be considered a very preliminary
overview of the tropical cyclones that occur in each month. The cyclone
tracks (provided separately) will generally be based upon operational
warnings issued by the various tropical cyclone warning centers. The
information contained therein may differ somewhat from the tracking and
intensity information obtained from a "best-track" file which is based
on a detailed post-seasonal analysis of all available data. Information
on where to find official "best-track" files from the various warning
centers will be passed along from time to time.
The track files are not being sent via e-mail. They can be retrieved
from the archive sites listed below. (Note: I do have a limited e-mail
distribution list for the track files. If anyone wishes to receive
these via e-mail, please send me a message.)
Both the summaries and the track files are standard text files
created in DOS editor. Download to disk and use a viewer such as
Notepad or DOS editor to view the files.
The first summary in this series covered the month of October,
1997. Back issues can be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and
Chris Landsea):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph> OR http://64.235.42.210>
http://mpittweather.com>
ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
Another website where much information about tropical cyclones may
be found is the website for the UK Meteorological Office. Their site
contains a lot of statistical information about tropical cyclones
globally on a monthly basis. The URL is:
http://www.met-office.gov.uk/sec2/sec2cyclone/sec2cyclone.html>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the complete Annual Tropical
Cyclone Report (ATCR) for 2001 (2000-2001 season for the Southern
Hemisphere). ATCRs for earlier years are available also. Recently
added was the report for the Southern Hemisphere 2001-2002 season.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2001 Atlantic and Eastern North Pacific
tropical cyclones; also, preliminary storm reports for all the 2001
Atlantic and Eastern North Pacific cyclones are now available, as
well as track charts and reports on storms from earlier years.
The URL is: http://www.nhc.noaa.gov>
A special thanks to Michael Bath of McLeans Ridges, New South Wales,
Australia, for assisting me with proofreading the summaries.
PREPARED BY
Gary Padgett
E-mail: garyp@alaweb.com
Phone: 334-222-5327
John Wallace (Eastern North Pacific, North Indian Ocean, Western
Gulf of Mexico)
E-mail: dosidicus@aol.com
Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South
China Sea)
E-mail: newchapelobservatory@btinternet.com
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: saclarke@iprimus.com.au
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